Microelectromechanical system (MEMS) devices such as actuators, switches, motors, sensors, variable capacitors, spatial light modulators (SLMs) and similar microelectronic devices can have movable elements. For example, a typical SLM device comprises an array of movable elements in the form of individually addressable light modulator elements whose respective “on” or “off” positions are set in response to input data to either pass or block transmission or reflectance of light directed at the array from an illumination source. In the case of an SLM device used in an image projection system, the input data corresponds to bits of bit frames generated from pixel hue and intensity information data of an image frame of an image input signal. The bit frames may be compilations of bits in a pulse-width modulation scheme that utilizes weighted time segment “on” or “off” periods for generation of corresponding pixel hue and intensity by eye integration during a given available image frame display period. A representative example of an SLM device includes a digital micromirror device (DMD), such as a Texas Instruments DLP™ micromirror array device. DLP™ devices have been employed widely commercially including in televisions, cinemagraphic projection systems, business-related projectors, and picoprojectors.
The mechanical performance of the moving elements within a MEMS device can be compromised by unintended adhesion. This type of adhesion can be reduced by coating contacting elements of the MEMS device with a coating such as a passivating agent or lubricant. The coating can be added to address several problems with device operation. One such problem is static friction (stiction). Another problem can include dynamic friction, which arises from the contact of moving elements in the device. Effective coatings can aid in reducing stiction and dynamic friction by reducing the surface energy of the device. For rotating devices (such as a micromirror supported for rotation on a hinge in a DMD), repeated movement displaces molecules and permanently biases the zero state of the rotation. Passivation layers may reduce this hinge memory accumulation by stabilizing certain states of the surface.